1 files changed, 42 insertions, 0 deletions
diff --git a/packages/astro-prism/src/highlighter.ts b/packages/astro-prism/src/highlighter.ts
new file mode 100644
index 000000000..3dffefae9
--- /dev/null
+++ b/packages/astro-prism/src/highlighter.ts
@@ -0,0 +1,42 @@
+import Prism from 'prismjs';
+import loadLanguages from 'prismjs/components/index.js';
+import { addAstro } from './plugin.js';
+
+const languageMap = new Map([['ts', 'typescript']]);
+
+export function runHighlighterWithAstro(lang: string | undefined, code: string) {
+	let classLanguage = `language-${lang}`;
+
+	if (!lang) {
+		lang = 'plaintext';
+	}
+
+	const ensureLoaded = (language: string) => {
+		if (language && !Prism.languages[language]) {
+			loadLanguages([language]);
+		}
+	};
+
+	if (languageMap.has(lang)) {
+		ensureLoaded(languageMap.get(lang)!);
+	} else if (lang === 'astro') {
+		ensureLoaded('typescript');
+		addAstro(Prism);
+	} else {
+		ensureLoaded('markup-templating'); // Prism expects this to exist for a number of other langs
+		ensureLoaded(lang);
+	}
+
+	if (lang && !Prism.languages[lang]) {
+		// eslint-disable-next-line no-console
+		console.warn(`Unable to load the language: ${lang}`);
+	}
+
+	const grammar = Prism.languages[lang];
+	let html = code;
+	if (grammar) {
+		html = Prism.highlight(code, grammar, lang);
+	}
+
+	return { classLanguage, html };
+}